Unruly party's tart (6)
I believe the answer is:
pastry
'tart' is the definition.
(thesaurus)
'unruly party's' is the wordplay.
'unruly' is an anagram indicator.
'partys' with letters rearranged gives 'PASTRY'.
(Other definitions for pastry that I've seen before include "'It may be puff, shortcrust and flakey (6)'" , "Foodstuff flattened with a rolling pin" , "See 7 Down" , "'Dough of flour, fat and water (6)'" , "Dough of flour, water and shortening" .)